JP4220133B2 - Two-component developer - Google Patents

Description

（上記式中、Ｒ１は水素原子、炭素原子数１〜４のアルキル基またはフェニル基、Ｒ２およびＲ３は水素基、炭素原子数１〜４のアルコキシ基、フェニル基、フェノキシ基、炭素原子数２〜４のアルケニル基、炭素原子数２〜４のアルケニルオキシ基、ヒドロキシ基、カルボキシル基、エチレンオキシド基、グリシジル基または下記式で示される基である。
【化２】

上記式中、Ｒ４、Ｒ５はヒドロキシ基、カルボキシル基、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基、炭素原子数２〜４のアルケニル基、炭素原子数２〜４のアルケニルオキシ基、フェニル基、フェノキシ基、ｋ、ｌ、ｍ、ｎ、ｏ、ｐは１以上の整数を示す。）
上記各置換基は未置換のもののほか、例えばアミノ基、ヒドロキシ基、カルボキシル基、メルカプト基、アルキル基、フェニル基、エチレンオキサイド基、グリシジル基、ハロゲン原子のような置換基を有してもよい。
【００２８】
また前記したように樹脂粒子及び／又は被覆層に分散されるキャリア粒子の体積固有抵抗を制御するために使用される低抵抗材料（導電材）は、従来、公知の物で良く、その例としては、鉄、金、銅等の金属；フェライト、マグネタイト等の酸化鉄；白色系導電剤（酸化チタン系、酸化スズ系、酸化亜鉛系）；カーボンブラック等の顔料が挙げられる。この中でも特にカーボンブラックの一つであるファーネスブラックとアセチレンブラックの混合物を用いることにより、少量の低抵抗微粉末の添加で効果的に導電性の調整が可能で、更に樹脂粒子／被覆層の耐摩耗性に優れたキャリア粒子を得ることができる。これらの低抵抗微粉末は、粒径０．０１〜１０μｍ程度のものが好ましく、樹脂粒子または被覆樹脂１００重量部に対して１〜３０重量部添加されることが好ましく、さらには２〜２０重量部が好ましい。また、電荷付与部材樹脂粒子及び／又は被覆層中には核体粒子との接着性を向上させたり導電性付与剤の分散性を向上させる目的でシランカップリング剤、チタンカップリング剤等を添加しても良い。
【００２９】
本発明で用いるシランカップリング剤としては下記一般式で示される化合物が挙げられる。
ＹＲＳｉＸ_３
（式中、Ｘはけい素原子に結合している加水分解基でクロル基、アルコキシ基、アセトキシ基、アルキルアミノ基、プロペノキシ基などである。
Ｙは有機マトリックスと反応する有機官能基でビニル基、メタクリル基、エポキシ基、グリシドキシ基、アミノ基、メルカプト基などである。
Ｒは炭素原子数１〜２０のアルキル基またはアルキレン基である。）
このシランカップリング剤の中でも、特に負帯電性を有する現像剤を得るにはＹにアミノ基を有するアミノシランカップリング剤が好ましく、正帯電性を有する現像剤を得るにはＹにエポキシ基を有するエポキシシランカップリング剤が好ましい。
【００３０】
キャリア粒子の被覆層の形成法としては、従来と同様、キャリア核体粒子の表面に被覆層形成液を噴霧法、浸漬法、加熱型ニーダー、加熱型ヘンシェルミキサー等の手段で塗布すればよい。また、被覆層の厚さは０．１〜２０μｍが好ましい。
【００３１】
本発明のキャリア粒子は、球状粒子でその表面状態が溶融した不連続相により凹凸部を形成したものから成り、その表面に樹脂被覆層を設け、被覆後の球状粒子表面の凹凸部が判別することができるほどの被覆層を有したものからなるものが好ましい。
従って、芯材の表面は凸部であっても被覆層が存在し、キャリア抵抗が適度に保たれて、スペント化を押さえて長寿命（高耐久性）なキャリアとなる。つまり芯材の円周形状にそって、均一な被覆層を設けて、凸部は被覆層が凹部より薄く、反面、凹部は被覆層が厚くなている。このような構成にすることにより凸部の存在によって、キャリア抵抗の上昇を適度に抑制し、かつ凹部と凸部の存在のバランスによって、トナーとの帯電の立上り性を良好に保ち、しかもスペント・トナーの付着を発生させない。凸部に一部分でも露出部分があると、その部分のキャリアにトナーの付着が発生して帯電量の低下、トナー飛散の発生の要因につながる。
【００３２】
一方、芯材の表面の円周形状にそわないで殻のように被覆層を設けると（たまごのイメージで黄身が芯材）スペント・トナーの付着はなく、被覆層も厚くなるので現像部の撹拌に伴って、被覆層が膜削れを多少、発生しても全く、問題ない。しかし、キャリア抵抗が高くなるとか、帯電量が上昇するとか、画像濃度が低くなるとか、エッジ効果が発生して、ラインコピーでは問題ないがソッリドコピーでは画像の中心部が薄くなる不具合がカラー・コピーに顕著に発生する。
本発明の上記キャリアは、凸部の存在により特にキャリア抵抗の上昇を適度を押さえて、凹部の存在バランスによりトナーとの帯電性を良好にに保ち、長寿命（高耐久性）なキャリアである。
【００３３】
キャリア粒子の抵抗は１×１０^８〜１×１０^１５Ωｃｍが良い。１×１０^１５Ωｃｍを越えると、エッジ効果が大きく、画像のザラツキ感が大きい。また、文字コピーでは特に大きな問題とはならないが、カラーコピーであると絵をコピーした際には上記の不具合が大きくクローズアップされてしまう。さらに現像時にキャリアの穂が固くなり、スジ・ムラが生じやすくい。１×１０^８Ωｃｍ未満であると、キャリア付着が発生しやすくその物により潜像担持体に傷を付けて、潜像が乱れやすくなり画像品質が顕著に低下する。
この抵抗の測定方法としては次のようにして行う。即ち、２０℃／６０％ＲＨの環境下で、面積１０（長さ４ｃｍ、幅２．５ｃｍ）の電極板２枚を２ｍｍの間隔で対抗させて形成されているセル内にサンプルをあふれる程度入れた後、この状態で高さ１５ｍｍの位置から平板上にセルを落下させるタッピング操作を３０回繰り返して、キャリアサンプルをセル内に充填する。次にセル上の余分なキャリアを除去してから電極板に５００Ｖ／ｃｍの直流電界を印加して抵抗を求める。
【００３４】
【実施例】
以下、本発明を実施例に基づいて具体的に説明する。なお部は重量部を示す。
【００３５】
実施例１ トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径７．７５μｍ、５μｍ以下の個数％が１２．８５、１６μｍ以上の体積％が０．０７のトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：含クロム金属錯体 １．５部
上記トナー母体粒子１００部に対して、平均粒径０．０１５μｍのシリカを０．３部の割合で混合して負帯電性の現像用トナーを作成した。
一方、キャリアは２−ヒドロキシエチルメタルリレート／メチルメタクリレート／スチレン共重合体とビニリデンフルオロライド／テトラフルオロエチレン共重合体との７５／２５の重量比の樹脂混合物を、平均粒径５０μｍのフェライト芯材に０．７５重量％（芯材基準）をコーテイングしてキャリアを被覆し作成した。
【００３６】
次に、ステンレス製のポットを用意して（直径６０ｍｍ、高さ６０ｍｍ、容積５０ｃｍ^３）前記トナーとキャリアの合計量が５０ｇになるように計量した。トナー濃度は１．５重量％（トナー＝０．７５ｇ、キャリア＝４９．２５ｇを計量）に設定し、トナーとキャリアをポットに仕込み、１５０ｒｐｍで１０分間の混合を実施した後現像剤のトナーの帯電量（Ｑ／Ｍ）を測定した。この時、トナーはトナー母体粒子に外添剤を添加後のトナー粒子からなるものであり、同様にしてトナー母体粒子を仕込み、帯電量（Ｑ／Ｍ）を測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝−１７
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−２１
Ｃ：シリカの平均粒径０．０１５μｍ
Ｄ：トナー母体粒子の平均粒径７．７５μｍ
Ｘ＝０．００２４
【００３７】
複写機に現像剤をセットしてテストするために、上記トナー２．５部に対して、キャリアとの総量が１００部になるような割合で混合して二成分系現像剤を作成した。そして、イマジオ４２０（リコー製複写機）を改造して、リサイクルトナーがトナー補給部に戻るようにした。この電子写真装置に上記現像剤をセットして初期の画像出しをしたところ良好な画像がえられた。更に、１０００００枚の連続通紙テストをしたところ良好な画像でしかもトナー飛散の発生が複写機内で見られず、また、複写プロセスを途中でストップして、潜像担持体上を観察したところトナーによる汚れは見られなく、全く問題がないことを確認した。その後１０℃／１５％、３０℃／９０％のそれぞれの環境で各１００００枚連続通紙のテストを実施したが特に問題は発生しなかった。
【００３８】
比較例１
トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径３．６μｍのトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：含クロム金属錯体 ０．２部
上記トナー母体粒子１００部に対して、平均粒径０．２９μｍのシリカを０．７部の割合で混合して負帯電性の現像用トナーを作成した。
一方、キャリアは２−ヒドロキシエチルメタルリレート／メチルメタクリレート／スチレン共重合体とビニリデンフルオロライド／テトラフルオロエチレン共重合体との８０／２０の重量比の樹脂混合物を、平均粒径５０μｍのフェライト芯材に０．７５重量％（芯材基準）をコーテイングしてキャリアを被覆し作成した。
【００３９】
次に、ステンレス製のポットを用意して（直径６０ｍｍ、高さ６０ｍｍ、容積５０ｃｍ^３）前記トナーとキャリアの合計量が５０ｇになるように計量した。トナー濃度は１．５重量％（トナー＝０．７５ｇ、キャリア＝４９．２５ｇを計量）に設定して、トナーとキャリアをポットに仕込み、１５０ｒｐｍで１０分間の混合した後現像剤のトナーの帯電量（Ｑ／Ｍ）を測定した。この時、トナーはトナー母体粒子に外添剤を添加後のトナー粒子からなるものであり、同様にしてトナー母体粒子を仕込み、帯電量（Ｑ／Ｍ）を測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝１
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−３５
Ｃ：シリカの平均粒径０．２９μｍ
Ｄ：トナー母体粒子の平均粒径３．６μｍ
Ｘ＝−２．８
【００４０】
複写機に現像剤をセットしてテストするために、上記トナー２．５部に対して、キャリアとの総量が１００部になるような割合で混合して二成分系現像剤を作成した。そして、イマジオ４２０（リコー製複写機）を改造して、リサイクルトナーがトナー補給部に戻るようにした。この電子写真装置に上記現像剤をセットして初期の画像出しをしたところ画像濃度は低く、画像ムラが極めて多い画像であった。
更に、１０００枚の連続通紙テストをしたところ画像は地汚れがさらに多くなり、しかもトナー飛散が複写機内に著しく発生し、また、複写プロセスを途中でストップして、潜像担持体上を観察したところトナーによる汚れ及び添加剤が著しく多くあることを確認した。この時点で現像剤を電子顕微鏡（ＳＥＭ）で観察したところ浮遊した添加剤が多く確認された。
【００４１】
比較例２
トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径３．７μｍのトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：４級アンモニウム塩 ０．２部
上記トナー母体粒子１００部に対して、平均粒径０．３１μｍのシリカを０．７部の割合で混合して正帯電性の現像用トナーを作成した。
一方、キャリアは２−ヒドロキシエチルメタルリレート／メチルメタクリレート／スチレン共重合体とビニリデンフルオロライド／テトラフルオロエチレン共重合体との２０／８０の重量比の樹脂混合物を、平均粒径５０μｍのフェライト芯材に０．７５重量％（芯材基準）をコーテイングしてキャリアを被覆し作成した。
【００４２】
次に、ステンレス製のポットを用意して（直径６０ｍｍ、高さ６０ｍｍ、容積５０ｃｍ^３）前記トナーとキャリアの合計量が５０ｇになるように計量した。トナー濃度は１．５重量％（トナー＝０．７５ｇ、キャリア＝４９．２５ｇを計量）に設定して、トナーとキャリアをポットに仕込み、１５０ｒｐｍで１０分間の混合を実施した後現像剤の帯電量（Ｑ／Ｍ）を測定した。この時、トナーはトナー母体粒子に外添剤を添加した後のトナー粒子からなるものであり、同様にしてトナー母体粒子を仕込み、帯電量（Ｑ／Ｍ）を測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝１
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝３１
Ｃ：シリカの平均粒径０．３１μｍ
Ｄ：トナー母体粒子の平均粒径３．７μｍ
Ｘ＝２．６
【００４３】
複写機に現像剤をセットしてテストするために上記トナー２．５部に対して、キャリアとの総量が１００部になるような割合で混合して二成分系現像剤を作成した。そして、スピリオ２２１０（リコー製複写機）を改造して、リサイクルトナーがトナー補給部に戻るようにした。この電子写真装置に上記現像剤をセットして初期の画像出しをしたところ画像濃度は低く、画像ムラが極めて多い画像であった。更に、１０００枚の連続通紙テストをしたところ画像は地汚れがさらに多くなり、しかもトナー飛散が複写機内に著しく発生し、また、複写プロセスを途中でストップして潜像担持体上を観察したところトナーによる汚れ及び添加剤が著しく多くあることを確認した。この時点で現像剤を電子顕微鏡（ＳＥＭ）で観察したところ浮遊した添加剤が多く確認された。
【００４４】
実施例２
トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径４．５μｍのトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：含クロム金属錯体 ０．２部
上記トナー母体粒子１００部に対して、平均粒径０．３μｍのシリカを０．７部の割合で混合して負帯電性の現像用トナーを作成した。
一方、キャリアは２−ヒドロキシエチルメタルリレート／メチルメタクリレート／スチレン共重合体とビニリデンフルオロライド／テトラフルオロエチレン共重合体との７５／２５の重量比の樹脂混合物を、平均粒径５０μｍのフェライト芯材に０．７５重量％（芯材基準）をコーテイングしてキャリアを被覆し作成した。
【００４５】
次に、ステンレス製のポットを用意して（直径６０ｍｍ、高さ６０ｍｍ、容積５０ｃｍ^３）前記トナーとキャリアの合計量が５０ｇになるように計量した。トナー濃度は１．５重量％（トナー＝０．７５ｇ、キャリア＝４９．２５ｇを計量）に設定して、トナーとキャリアをポットに仕込み、１５０ｒｐｍで１０分間の混合を実施した後現像剤の帯電量（Ｑ／Ｍ）を測定した。この時トナーは、トナー母体粒子に外添剤を添加した後のトナー粒子からなるものであり、同様にしてトナー母体粒子を仕込み、帯電量（Ｑ／Ｍ）を測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝１
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−３５
Ｃ：シリカの平均粒径０．３μｍ
Ｄ：トナー母体粒子の平均粒径４．５μｍ
Ｘ＝−２．３
【００４６】
複写機に現像剤をセットしてテストするために、上記トナー２．５部に対して、キャリアとの総量が１００部になるような割合で混合して二成分系現像剤を作成した。そして、イマジオ４２０（リコー製複写機）を改造して、リサイクルトナーがトナー補給部に戻るようにした。この電子写真装置に上記現像剤をセットして初期の画像出しをしたところ良好な画像が得られた。更に、１０００００枚の連続通紙テストをしたところ良好な画像でしかもトナー飛散の発生が複写機内で見られず、また、複写プロセスを途中でストップして、潜像担持体上を観察したところトナーによる汚れは見られなく、全く問題がないことを確認した。その後１０℃／１５％、３０℃／９０％のそれぞれの環境で各１００００枚連続通紙のテストを実施したが特に問題は発生しなかった。
【００４７】
実施例３
トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径４．５μｍのトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：４級アンモニウム塩 ０．２部
上記トナー母体粒子１００部に対して、平均粒径０．３μｍのシリカを０．７部の割合で混合して正帯電性の現像用トナーを作成した。
一方、キャリアは２−ヒドロキシエチルメタルリレート／メチルメタクリレート／スチレン共重合体とビニリデンフルオロライド／テトラフルオロエチレン共重合体との２０／８０の重量比の樹脂混合物を、平均粒径５０μｍのフェライト芯材に０．７５重量％（芯材基準）をコーテイングしてキャリアを被覆し作成した。
【００４８】
次に、ステンレス製のポットを用意して（直径６０ｍｍ、高さ６０ｍｍ、容積５０ｃｍ^３）前記トナーとキャリアの合計量が５０ｇになるように計量した。トナー濃度は１．５重量％（トナー＝０．７５ｇ、キャリア＝４９．２５ｇを計量）に設定して、トナーとキャリアをポットに仕込み、１５０ｒｐｍで１０分間の混合を実施した後現像剤の帯電量（Ｑ／Ｍ）を測定した。この時のトナーは、トナー母体粒子に外添剤を添加後のトナー粒子からなるものであり、同様にしてトナー母体粒子を仕込み、帯電量（Ｑ／Ｍ）を測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝１
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝３５
Ｃ：シリカの平均粒径０．３μｍ
Ｄ：トナー母体粒子の平均粒径４．５μｍ
Ｘ＝２．３
【００４９】
複写機に現像剤をセットしてテストするために、上記トナー２．５部に対して、キャリアとの総量が１００部になるような割合で混合して二成分系現像剤を作成した。そして、スピリオ２２１０リコー製複写機）を改造して、リサイクルトナーがトナー補給部に戻るようにした。この電子写真装置に上記現像剤をセットして初期の画像出しをしたところ良好な画像が得られた。更に、１０００００枚の連続通紙テストをしたところ良好な画像でしかもトナー飛散の発生が複写機内で見られず、また、複写プロセスを途中でストップして、潜像担持体上を観察したところトナーによる汚れは見られなく、全く問題がないことを確認した。その後１０℃／１５％、３０℃／９０％のそれぞれの環境で各１００００枚連続通紙のテストを実施したが特に問題は発生しなかった。
【００５０】
実施例４
実施例１において、トナー処方の中で電荷制御剤を含クロム金属錯体からサリチル酸亜鉛誘導体（ボントロンＥ８４、オリエント化学社製）に代えた以外は実施例１と同様にしてトナーを作成して、同様にしてテストしところ実施例１と同様の結果を得た。
【００５１】
実施例５
トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径７．７５μｍ、５μｍ以下の個数％が１２．８５、１６μ以上の体積％が０．０７のトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：含クロム金属錯体 １．５部
上記トナー母体粒子１００部に対して、平均粒径０．０１８μｍのシリカを０．６部と平均粒径０．０２３μｍのチタンを０．２部を混合して負帯電性の現像用トナーを作成した。キャリアは実施例１と同様のものを用い、実施例１と同様にして現像剤を作成して、それぞれの帯電量（Ｑ／Ｍ）を測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝−１７
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−１９
Ｃ：（シリカの平均粒径０．０１８μｍ）＋（チタンの平均粒径０．０２３μｍ）＝０．０４１
Ｄ：トナー母体粒子の平均粒径７．７５μｍ
Ｘ＝０．００５９
次に実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００５２】
実施例６
実施例１において、シリカを有機シリコンコンパウンドで処理した物（ＴＳ−７２０、キャボット社製）に代えた以外は実施例１と同様にしてテストしたところ、実施例１と同様の結果を得た。
【００５３】
実施例７
実施例１において、トナー処方の中で電荷制御剤を含クロム金属錯体からサリチル酸鉄塩に代えた以外は実施例１と同様にしてトナー、現像剤を作成して、同様にしてテストしところ、実施例１と同様の結果を得た。
【００５４】
実施例８
トナーは下記処方の混合物を２本ロールの加熱下で混練して、その後冷却後、粗粉砕し、粉砕分級して平均粒径７．７５μｍのトナー母体粒子を得た。
結着樹脂：スチレン／アクリル樹脂 １００部
着色剤：カーボンブラック １１部
電荷制御剤：含クロム金属錯体 １．５部
ワックス：パラフィンワクッス ５．５部
上記トナー母体粒子１００部に対して、平均粒径０．０１５μｍのシリカを０．３部の割合で混合して負帯電性の現像用トナーを作成した。一方、キャリアは実施例１のものを使用して、実施例１と同様にしてテストしたところ、実施例１と同様の結果を得た。
【００５５】
実施例９
トナーは実施例１のものを使用した。
一方、キャリアの作成に際して下記処方によりコーテイング液を調整した。
シリコン樹脂液：ＳＲ２４１１（トーレダウコーニング社製） ３００部
トルエン １５００部
上記コーテイング液で凹凸を有した芯材表面からなる平均粒径５０μｍのフェライトに被覆した。被覆後２３０℃にて、２時間加熱してシリコン膜の硬化を行い被覆層を有するキャリア粒子を得た。被覆したキャリア粒子の表面を走査型電子顕微鏡（ＳＥＭ）、走査型トンネル顕微鏡（ＳＴＭ）で観察したところ被覆後であっても表面の凹凸が明確に観察できた。また電子線マイクロアナライザーで凸部にもＳｉ元素が存在することが確認できた。
このキャリアおよびトナーを用いて、実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００５６】
実施例１０
トナーは実施例１のものを使用した。
一方、キャリアの作成において下記処方によりコーテイング液を調整した。そして、実施例９と同様にして芯材に被覆した。
シリコン樹脂液：ＳＲ２４１１（トーレダウコーニング社製） ３００部
導電剤：ケチェンブラックＥＣＤＪ６００ ４部
（ライオンアクゾ社製） トルエン １５００部
このキャリアおよびトナーを用いて、実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００５７】
実施例１１
トナーは実施例１のものを使用した。
一方、キャリアの作成において下記処方によりコーテイング液を調整した。そして、実施例９と同様にして芯材に被覆した。
シリコン樹脂液：ＳＲ２４１１（トーレダウコーニング社製） ３００部
導電剤：ケチェンブラックＥＣＤＪ６００ ４部
（ライオンアクゾ社製）
カップリング剤：ＫＢＭ６０３（信越化学社製） ８部
トルエン １５００部
このキャリアおよびトナーを用いて、実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００５８】
実施例１２
＜イエロー・トナー＞
下記トナー処方によりイエロー・トナーを作成した。
ポリエステル樹脂 １００部
イエロー着色剤：Ｃ．Ｉ．ピグメントイエロー１８０ ５部
電荷制御剤：サリチル酸Ｚｎ塩（ボントロンＥ８４、オリエント化学社製） ２部
上記処方の混合物をミキサーで予備混練を実施した。その後３本ロールミルで溶融混練をして、冷却後０．５〜３ｍｍに粗粉砕した後、更に粉砕と分級を行い平均粒径７．７５μｍ、５μｍ以下の個数％が１２．８５、１６μｍ以上の体積％が０．０７のイエロートナーを得た。
【００５９】
上記トナー１００部に対して、０．０１６μｍのシリカ微粉体Ｒ９７２（日本アエロジル社製）を０．５部の割合で混合して負帯電性のトナーを得た。
一方、キャリアは実施例９のものを使用して、トナー母体粒子のみとトナー母体粒子に外添剤を添加後のトナー粒子からなるもののそれぞれの帯電量を実施例１と同様にして測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝−１８
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−２３
Ｃ：シリカの平均粒径０．０１６μｍ
Ｄ：トナー母体粒子の平均粒径７．７５μｍ
Ｘ＝０．００２６
【００６０】
＜マゼンタ・トナー＞
下記トナー処方によりマゼンタ・トナーを作成した。
ポリエステル樹脂 １００部
マゼンタ着色剤：Ｃ．Ｉ．ピグメントレッド１２２ ４部
電荷制御剤：サリチル酸Ｚｎ塩（ボントロンＥ８４、オリエント化学社製） ２部
上記処方の混合物をミキサーで予備混練を実施した。その後３本ロールミルで溶融混練をして、冷却後０．５〜３ｍｍに粗粉砕した後、更に粉砕と分級を行い平均粒径７．７５μｍ、５μｍ以下の個数％が１２．８５、１６μｍ以上の体積％が０．０７のマゼンタトナーを得た。
【００６１】
上記トナー１００部に対して、０．０１６μｍのシリカ微粉体Ｒ９７２（日本アエロジル社製）を０．５部の割合で混合して負帯電性のトナーを得た。
一方、キャリアは実施例９のものを使用して、トナー母体粒子のみとトナー母体粒子に外添剤を添加後のトナー粒子からなるもののそれぞれの帯電量を実施例１と同様にして測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝−１４
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−１９
Ｃ：シリカの平均粒径０．０１６μｍ
Ｄ：トナー母体粒子の平均粒径７．７５μｍ
Ｘ＝０．００２８
【００６２】
＜シアン・トナー＞
下記トナー処方によりシアン・トナーを作成した。
ポリエステル樹脂 １００部
シアン着色剤：Ｃ．Ｉ．ピグメントブル−１５：３ ３部
電荷制御剤：サリチル酸Ｚｎ塩（ボントロンＥ８４、オリエント化学社製） ２部
上記処方の混合物をミキサーで予備混練を実施した。その後３本ロールミルで溶融混練をして、冷却後０．５〜３ｍｍに粗粉砕した後、更に粉砕と分級を行い平均粒径７．７５μｍ、５μｍ以下の個数％が１２．８５、１６μｍ以上の体積％が０．０７のシアントナーを得た。
【００６３】
上記トナー１００部に対して、０．０１６μｍのシリカ微粉体Ｒ９７２（日本アエロジル社製）を０．５部の割合で混合して負帯電性のトナーを得た。
一方、キャリアは実施例９のものを使用して、トナー母体粒子のみとトナー母体粒子に外添剤を添加後のトナー粒子からなるもののそれぞれの帯電量を実施例１と同様にして測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝−１８
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−２２
Ｃ：シリカの平均粒径０．０１６μｍ
Ｄ：トナー母体粒子の平均粒径７．７５μｍ
Ｘ＝０．００２５
【００６４】
＜ブラック・トナー＞
下記トナー処方によりブラック・トナーを作成した。
ポリエステル樹脂 １００部
ブラック着色剤：カーボンブラック ８部
電荷制御剤：サリチル酸Ｚｎ塩（ボントロンＥ８４、オリエント化学社製） ２部
上記処方の混合物をミキサーで予備混練を実施した。その後３本ロールミルで溶融混練をして、冷却後０．５〜３ｍｍに粗粉砕した後、更に粉砕と分級を行い平均粒径７．７５μｍ、５μｍ以下の個数％が１２．８５、１６μｍ以上の体積％が０．０７のブラックトナーを得た。
【００６５】
上記トナー１００部に対して、０．０１６μｍのシリカ微粉体Ｒ９７２（日本アエロジル社製）を０．５部の割合で混合して負帯電性のトナーを得た。
一方、キャリアは実施例９のものを使用して、トナー母体粒子のみとトナー母体粒子に外添剤を添加後のトナー粒子からなるもののそれぞれの帯電量を実施例１と同様にして測定した。その結果は次のようである。
Ａ：トナー母体粒子のＱ／Ｍ＝−１３
Ｂ：外添剤を添加後のトナー粒子のＱ／Ｍ＝−１８
Ｃ：シリカの平均粒径０．０１６μｍ
Ｄ：トナー母体粒子の平均粒径７．７５μｍ
Ｘ＝０．００２９
【００６６】
次に、キャリアは実施例９の物を使用して、前記各色のトナー５部とキャリアとの総量が１００部の割合で混合して、イエロー、マゼンタ、シアン、ブラックの各現像剤を作成した。この各色の現像剤はプリテール７５０（リコー製カラー複写機）を改造して、リサイクルトナーがトナー補給部に戻るようにした複写機にセットして画像を出したところトナー転写性が良く、画像部のトナーチリがなく、文字部のトナー抜けもなく、適度の画像光沢を維持し、地汚れもなく、良好な画像が得られた。また、１０℃／３０％、３０℃／９０％のそれぞれの環境で画像を出した後、それぞれの環境で１００００枚コピー後の画像のいずれであっても良好な画像が得られた。
【００６７】
実施例１３
トナーは実施例１のものを使用した。
一方、キャリアは下記処方によりコーティング液を調整し芯材に被覆して作成した。
ヒドロキシル基を有するアクリル樹脂の合成例：攪拌機にて、攪拌しながら窒素気流中でキシレン７００ｇ、ブタノール３００ｇを仕込み、１００℃に昇温し、スチレン４００ｇ、メチルメタクリレート１６０ｇ、ｎ−ブチルアクリレート２００ｇ、メタクリル酸３０ｇ、２−ヒドロキシエチルアクリレート１００ｇ、及び重合開始剤としてアゾビスイソブチロニトリル１０ｇの混合物を５時間かけて滴下した。その後内容物を更に６時間反応させて、固形分５０重量％の樹脂を得た。（水酸基価：４１ＫＯＨｍｇ／ｇ、数平均分子量１４００）
Ｃｕ−Ｚｎフェライト（パウダーテック社製、平均粒径５０μｍ、Ｆ−３００） １０００部
完全置換型メチル化ベンゾグアナミン（重合度１．６５、固形分７７重量％） ２．６部
アクリル樹脂（上記合成品：固形分５０重量％） １０部
トルエン ３００部
上記メチル化グアナミンとアクリル樹脂とトルエンを混合してコーティング液を調整した。上記フェライトを投入した流動床式コーティング装置の温度を約６０℃に保ちコーティング液を噴霧した。スプレー終了後、約１０分乾燥させ取り出した。次にこのキャリアを電気炉にて１５０℃で１時間処理し、冷却後解砕して膜厚０．２μｍの樹脂被覆キャリアを得た。
このキャリアおよびトナーを用いて、実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００６８】
実施例１４
トナーは実施例１のものを使用した。
一方、キャリアは下記処方によりコーティング液を調整し芯材に被覆して作成した。
ヒドロキシル基を有するアクリル樹脂の合成例：攪拌機にて、攪拌しながら窒素気流中でキシレン７００ｇ、ブタノール３００ｇを仕込み、１００℃に昇温し、スチレン４００ｇ、メチルメタクリレート１６０ｇ、ｎ−ブチルアクリレート２００ｇ、メタクリル酸３０ｇ、２−ヒドロキシエチルアクリレート１００ｇ、及び重合開始剤としてアゾビスイソブチロニトリル１０ｇの混合物を５時間かけて滴下した。その後内容物を更に６時間反応させて、固形分５０重量％の樹脂を得た。（水酸基価：４１ＫＯＨｍｇ／ｇ、数平均分子量１４００） Ｃｕ−Ｚｎフェライト（パウダーテック社製、平均粒径５０μｍ、Ｆ−３００） １０００部
完全置換型メチル化ベンゾグアナミン（重合度１．６５、固形分７７重量％） ２．６部
アクリル樹脂（上記合成品：固形分５０重量％） １０部
導電材：ケチェンブラックＥＣＤＪ６００ ２．５部
（ライオンアクゾ社製）
トルエン ３００部
上記メチル化グアナミンとアクリル樹脂とトルエンを混合してコーティング液を調整した。上記フェライトを投入した流動床式コーティング装置の温度を約６０℃に保ちコーティング液を噴霧した。スプレー終了後、約１０分乾燥させ取り出した。次にこのキャリアを電気炉にて１５０℃で１時間処理し、冷却後解砕して膜厚０．２μｍの樹脂被覆キャリアを得た。
このキャリアおよびトナーを用いて、実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００６９】
実施例１５
次のようにして重合トナーを作成した。
スチレンモノマー ９０部
メタクリル酸ｎ−ブチル ５５部
帯電制御剤（スピロンブラックＴＲＨ 保土谷化学社製） ３５部
着色剤（ラーベン４１０ コロンビアケミカル社製） １３部
上記成分を配合し、重合開始剤（２，２−アゾビスイソブチロニトリル）と共に反応容器に入れて重合を行い、粒径６．８μｍのところで重合を停止して、この造粒した粒子を水洗した後乾燥して重合トナー粒子を得た。このトナーに実施例１と同じ添加剤を添加して、負帯電性の現像用トナーを作成した。
また、キャリアは実施例１の物を使用して、実施例１と同様にテストしたところ、実施例１と同様の結果を得た。
【００７０】
【発明の効果】
本発明は、トナー母体粒子の帯電量をＡ、トナー母体粒子に外添剤を添加した後のトナー帯電量Ｂ、外添剤の平均粒径の和をΣＣ、トナー母体粒径をＤとしたとき、下記関係式を満足するトナーを用いたことにより、クリーニングされたトナーをリサイクルしても、機内でのトナー飛散もなく、静電潜像担持体の汚れも生じることがなく、しかも、種々の環境下で連続通紙しても画質の劣化のない優れた画像を形成することができる二成分系現像剤を提供することができる。
Ｘ＝（Ｂ／Ａ）×（ΣＣ／Ｄ）
−２．３≦Ｘ≦２．３ （但し、Ｘ≠０）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-component developer for developing an electrostatic latent image with toner to form an image.
[0002]
[Prior art]
In general, in an electrophotographic apparatus, a latent image on an electrostatic latent image carrier is developed with colored particles (toner), the toner image is transferred to a transfer member, and then the toner image is fixed by a fixing device. The electrostatic latent image carrier after the toner transfer is not transferred and the remaining toner is cleaned by a cleaning device, collected in a collection container, and discarded. If the residual toner can be reused and effectively used as recycled toner, resources can be effectively used. However, when recycled toner is used, paper dust from the transfer paper is mixed in, and toner that has been embedded or peeled off from the external additive is mixed in, so problems such as background contamination and toner scattering are likely to occur. There is. In using recycled toner, Japanese Patent Application Laid-Open No. 7-209902 proposes a method for suppressing the deterioration of the carrier and improving the durability performance by defining the amount of the release agent and the amount of the external additive. Japanese Patent Application Laid-Open No. 11-95553 discloses that the flowability and charging stability of a developer are improved by a combination of toners that maintains a relationship in which the amount of external additive of initial toner is less than the amount of external additive of replenishment toner. Proposed. Japanese Patent Laid-Open No. 11-153881 discloses that a toner added with two types of fine particles having a specified sphericity is added with a toner charge amount and a base charge amount with no additive added. In such a case, a toner having a high transfer efficiency and a reduced amount of waste toner has been proposed so as to be between the charged amounts.
[0003]
However, these technologies have not sufficiently solved the above problems in toner recycling.
[0004]
[Problems to be solved by the invention]
In the present invention, when an electrostatic latent image on an electrostatic latent image carrier is developed with toner and then transferred and fixed to form an image, the electrostatic latent image carrier is cleaned after the transfer. Recycling the used toner will not cause the toner to scatter in the machine, will not cause contamination of the electrostatic latent image carrier, and will not degrade image quality even when images are formed by continuously passing a large number of sheets. An object is to provide a two-component developer capable of forming an excellent image.
[0005]
[Means for Solving the Problems]
According to the present invention, there is provided a method for developing an electrostatic latent image on an electrostatic latent image bearing member by a developing unit in which a toner layer is formed on a developer bearing member. A two-component developer composed of a carrier and a toner is accommodated. The developer is circulated and conveyed on the developer carrying member, and an electrostatic latent image is developed in a developing area in a gap between the developer and the opposite electrostatic latent image carrier. The toner image formed on the electrostatic latent image carrier is transferred onto the transfer member one or more times, and the electrostatic latent image carrier is cleaned by the cleaning unit. The cleaned toner is returned to the developing unit or the replenishing toner unit via the toner recovery device and reused as recycled toner. Thereafter, the electrostatic latent image carrier forms the next electrostatic latent image. In addition, the toner image is transferred to the final transfer member. After that, the two-component developer used in the image forming method to be fixed by the fixing unit, wherein the toner particles constituting the developer are at least mother particles composed of a colorant, a binder resin, and a charge control agent. It is composed of one or more external additives added. The charge amount of the toner base particles is A, the toner charge amount after adding the external additive to the toner base particles is B, and the sum of the average particle diameters of the external additives Is a two-component developer characterized by satisfying the following relational expression, where ΣC is the average particle size of the toner base particles.
X = (B / A) × (ΣC / D)
-2.3 ≦ X ≦ 2.3 (where X ≠ 0)
According to the invention, there is provided the above two-component developer, wherein the charge control agent is a salicylic acid metal salt and / or a metal salt of a salicylic acid derivative.
According to the invention, the carrier particles are selected from silicon resin, fluorine resin, mixture of fluorine resin and styrene / acrylic copolymer, amino resin, mixture of amino resin and styrene / acrylic copolymer. Any one of the two-component developers described above is provided, which has a coating layer made of a resin.
Furthermore, according to the present invention, there is provided any one of the above two-component developers, wherein the carrier particles have a coating layer containing a conductive material.
Furthermore, according to the present invention, the carrier particles are spherical particles, and the surface crystal state thereof is formed by forming a concavo-convex portion by a discontinuous phase in which the crystal state is melted. The spherical particle surface has a coating layer that can be discriminated by uneven portions, and any one of the above two-component developers is provided.
[0006]
That is, the present invention is characterized by the toner used in the image forming method for recycling the toner cleaned in the cleaning unit, and at least the base particles composed of the colorant, the binder resin, and the charge control agent are included. The toner is composed of one or more external additives added, the charge amount of the toner base particles is A, the charge amount of the toner after adding the external additive to the toner base particles is B, and the average particle diameter of the external additive The following relational expression is satisfied, where ΣC is the sum of the above and D is the average particle diameter of the toner base particles.
X = (B / A) × (ΣC / D)
-2.3 ≦ X ≦ 2.3 (where X ≠ 0)
[0007]
In general, an external additive is added to the toner base particles. The purpose is to improve the fluidity of the toner, to prevent the carrier and the latent image carrier from being deteriorated by appropriately polishing the surface of the carrier and the latent image carrier, and to improve the charging property.
The external additive added to the toner base particles is removed from the toner base particles by mechanical stress in the recovery path of stirring in the developing device, cleaning device, or recovery from the cleaning device to the developing device. Separation, embedding (being embedded) in the toner base particles occurs.
[0008]
When such a phenomenon occurs, in particular, the chargeability of the toner particles becomes unstable, so that, for example, the image density in the copy quality becomes low, or the image density becomes too high, resulting in scumming.
In addition, toner scattering becomes significant in the machine, and further, the toner transfer efficiency is lowered, and it is too heavy to clean the latent image carrier in the cleaning process, so that the toner cannot be sufficiently cleaned. In addition, in a different environment, the amount of charge changes significantly in each environment, which promotes the above problem.
[0009]
Thus, when the external additive added to the toner base particles is detached or embedded in the toner base particles, the cause of the unstable charge amount of the toner is investigated. The charge amount A of the toner base particles and the toner It has been found that the charge amount becomes extremely unstable when the ratio (B / A) of the charge amount B of the toner after the addition of the external additive to the base particles is far away. That is, if this ratio is close to 1, it is almost in the form of A = B, and even if a phenomenon occurs in which the external additive added to the toner base particles is detached or embedded in the toner base particles, Since the charge amount is close to A = B, there is little change in the charge amount between the toner particle surface and the carrier particles. On the other hand, when this ratio is small or large, if the difference in charge amount from the carrier particles is remarkably large (the charge amount is far away), the external additive added to the toner base particles is detached or the toner base particles When the phenomenon of embedding occurs in the toner, the charge of the toner base particles and the carrier is dominant, and eventually the charge amount A of the toner base particles contributes to the charge in the developer. (Quantity) becomes unstable and causes the above-mentioned problems.
[0010]
In addition, external additives may be added in some cases as occasion demands. For this reason, different types of materials may aggregate to increase the particle size of the additive. Therefore, if the ratio (ΣC / D) of the sum ΣC of the average particle diameter of the external additive and the average particle diameter D of the toner base particle is too small, the external additive is converted into the toner base particle when the toner base particle and the external additive are mixed. It is easy to be buried. In addition, even when the temperature rises due to stirring in the developing unit during use in the machine, the effect of adding an external additive is hardly exhibited because the temperature is easily increased. On the other hand, if this ratio is too large, it is difficult for the external additive to adhere to or adhere to the toner base particles when the toner base particles and the external additive are mixed, and the amount of free external additives increases in the developer. The additive makes the charging unstable, damages the latent image carrier, and forms a latent image.
Furthermore, in roller fixing, if the roller surface is damaged or a release agent (silicone oil) is applied, the roller adheres to the application member and the release agent cannot be supplied, causing an offset. Further, since the external additive is remarkably easily removed during use in the machine, the above-mentioned problems are likely to occur at the same time.
[0011]
In view of this, the inventors of the present invention have a ratio (B / A) between the charge amount A of the toner base particles and the charge amount B of the toner after adding the external additive to the toner base particles, and the average particle size of the external additive. By defining the product of the two ratio values of the ratio of the sum of the diameters ΣC and the average particle diameter D of the toner base particles (ΣC / D) as described above, it has been found that an image with good image quality can be formed. The present invention has been completed.
[0012]
Entity Form of the Invention
The constituent materials of the two-component developer for image formation of the present invention will be described in detail below. (Binder resin)
As the binder resin of the toner of the present invention, all of the binder resins usually used in electrophotographic toners can be used. Specific examples thereof include styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene, and substitution thereof. Homopolymer of styrene / p-chlorostyrene copolymer, styrene / propylene copolymer, styrene / vinyltoluene copolymer, styrene / vinylnaphthalene copolymer, styrene / methyl acrylate copolymer, styrene / Ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer Styrene / α-chloromethyl methacrylate copolymer, styrene / acrylic Styrene copolymers such as nitrile copolymer, styrene / vinyl methyl ketone copolymer, styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / maleic acid copolymer; polymethyl acrylate, polyacryl (Meth) acrylic acid ester homopolymers such as butyl acid, polymethyl methacrylate and polybutyl methacrylate and their copolymers; polyvinyl polymers such as polyvinyl chloride and polyvinyl acetate; polyester polymers, polyurethane Polymer, polyamide polymer, polyimide polymer, polyol polymer, epoxy polymer, terpene polymer, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, etc. Alternatively, it can be used as a mixture, but is not particularly limited thereto. Among these, at least one selected from styrene / acrylic copolymers, polyester resins, and polyol resins is more preferable from the viewpoint of binding properties, electrical characteristics, cost, and the like.
[0013]
(Coloring agent)
Specific examples of the colorant of the toner of the present invention include the following.
<Coloring agent for black>
Carbon black, spirit black, aniline black (CI PIGMENT BLACK 1)
[0014]
<Colorant for yellow>
C. I. PIGMENT YELLOW 1
Symbol Fast Yellow GH-B (Dainippon Ink)
C. I. PIGMENT YELLOW 3
Symbol Fast Yellow 10GH (Dainippon Ink)
C. I. PIGMENT YELLOW 12
Linol Yellow GRO (Toyo Ink)
Symbol Fast Yellow GF (Dainippon Ink)
C. I. PIGMENT YELLOW 13
Symbol Fast Yellow GRF (Dainippon Ink)
C. I. PIGMENT YELLOW 14
Symbol Fast Yellow 5GF (Dainippon Ink)
C. I. PIGMENT YELLOW 17
Symbol Fast Yellow 8GF (Dainippon Ink)
Linol Yellow FGN (Toyo Ink)
C. I. PIGMENT YELLOW 154
Chromfine Yellow 2080 (Daiichi Seika)
C. I. PIGMENT YELLOW 180
PV Fast Yellow HG (Clariant)
[0015]
<Colorant for magenta>
C. I. PIGMENT RED 5
Symbol Fast Red 4188N (Dainippon Ink)
C. I. PIGMENT RED 22
Seikafast Scarlet G (Daiichi Seika)
Symbol Fast Scallet BG (Dainippon Ink)
C. I. PIGMENT RED 48: 1
Linol Red 2B FG-3303-G (Toyo Ink)
Simulator Red 3109 (Dainippon Ink)
C. I. PIGMENT RED 57: 1
Linol Red 6B FG-4215 (Toyo Ink)
Symbler Brilliant Carmine 6B273 (Dainippon Ink)
PV Rubine L6B (Clariant)
C. I. PIGMENT RED 112
Oriental Fast Red GR (Toyo Ink)
C. I. PIGMENT RED 114
Pollux Pink PM-2B (Sumika Color)
C. I. PIGMENT RED 122
Hostaperm Pink E 02 (Clariant)
Fastogen Super Magenta R (Dainippon Ink)
C. I. PIGMENT RED 166
Fastogen Super Red R (Dainippon Ink)
C. I. PIGMENT RED 184
Permanent Rubin F6B (Clariant)
[0016]
<Colorant for cyan>
C. I. PIGMENT BLUE 15: 3
Chromo fine Blue 4920 (Daiichi Seika)
Fastogen Blue FGF (Dainippon Ink)
Linol Blue FG-7351 (Toyo Ink)
C. I. PIGMENT BLUE 16
Heliogen Blue 16 (BASF)
C. I. PIGMENT GREEN 7
Phthalocyanine Green (Toyo Ink)
C. I. PIGMENT GREEN 36
Cyanine Green 2 YL (Toyo Ink)
[0017]
In the toner of the present invention, the amount of the colorant is suitably 0.1 to 50 parts by weight, more preferably 0.5 to 25 parts by weight with respect to 100 parts by weight of the binder resin.
[0018]
(Charge control agent)
The toner of the present invention contains a charge control agent. Any known charge control agent can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified) (Including quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts such as aromatic carboxylic acid metal compounds, and metal salts of salicylic acid derivatives. . In particular, the metal salt of salicylic acid, which is a metal compound of aromatic carboxylic acid, and the metal salt of salicylic acid derivative have a high charging speed and a uniform charge distribution, so that dirt on the electrostatic latent image carrier, toner scattering into the machine, image area It is preferable in that it does not cause background contamination.
[0019]
In the toner of the present invention, the amount of the charge control agent used is determined by the toner production method including the type of the binder resin, the additive used, and the dispersion method, but is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 1 to 5 parts by weight is preferable. If it is less than 0.1 part by weight, the toner is insufficiently charged and is not practical. If the amount exceeds 10 parts by weight, the chargeability of the toner is too high. In the case of a two-component developer, the electrostatic attraction force with the carrier increases, so that the developer fluidity and the image density decrease. Invite. The charge control agent may be used in combination with a plurality of charge control agents as necessary.
[0020]
In addition, an external additive is added to the toner of the present invention, and the amount of the external additive added to the toner base particles is preferably 0.02 to 6.5 parts by weight with respect to 100 parts by weight of the toner base. Preferably it is 0.05-4.8 weight part. This additive has a specific surface area of 25 to 450 m by nitrogen adsorption measured by the BET method.²Those in the range of / g generate good action.
Further, if necessary, it may be treated with a treating agent such as silicone oil, a coupling agent, an organic titanium compound or the like for the purpose of hydrophobization, charge control and the like.
Examples of such external additives include colloidal silica, hydrophobic silica, fatty acid metal salts (zinc stearate, aluminum stearate, etc.), metal oxides (titanium oxide, cerium oxide, silicon carbide, strontium titanate, oxidation) Aluminum, tin oxide, antimony oxide, etc.), fluoropolymers and the like.
[0021]
Furthermore, in order to use a so-called oil-less fixing method in which the toner of the present invention does not use a release agent such as oil at the time of toner fixing, waxes such as polyethylene wax, propylene wax, carnauba wax are included in the toner particles. It can be realized by adding. The amount of these used depends on the type of material used and the fixing method, but is preferably about 0.5 to 10.0% by weight, more preferably about 1.0 to 8.0% by weight. preferable.
[0022]
(Toner production method)
As a method for producing the toner particles of the present invention, the raw materials as described above are kneaded by a known method using a twin roll, a twin screw extrusion kneader, a single screw extrusion kneader, etc. The toner base particles can be prepared by known pulverization and classification. Alternatively, a toner may be directly produced from a monomer, a colorant, and an additive by a suspension polymerization method or a non-aqueous dispersion polymerization method.
[0023]
The toner particle diameter is preferably 3 to 10 μm, and if it exceeds 10 μm, it is difficult to obtain a smooth gradation and the resolution is also lowered. On the other hand, when the thickness is less than 3 μm, the rise of the charge amount is good, but the tendency of toner scattering and contamination of the carrier surface becomes remarkable.
The toner particle diameter is measured by connecting an interface for outputting the number distribution and the volume distribution by COULTER COUNTER MODELTA2 (manufactured by Coulter) and using a 10 μm aperture (pore). First, a toner measurement sample is dispersed in a surfactant added to an electrolytic aqueous solution. The sample is injected into another 1% NaCl electrolyte, and an electric current is passed between the electrodes through the electrolyte placed on both sides of the aperture of the aperture tube. From this resistance change, the particle size of particles of 2 to 40 μm The distribution is measured, and the volume average particle diameter is obtained from the volume average distribution.
[0024]
The toner particle size distribution is preferably 60% by number or less for toner having a particle size of 5 μm or less. Beyond this, the toner easily adheres to the carrier, and the carrier in the developer is not charged efficiently with respect to the replenished toner, so that it is easy for the toner to scatter in the machine and the image area to become dirty. End up. Further, the toners are likely to aggregate, and it is difficult to obtain a smooth image. Further, it is desirable that the toner particles having a particle diameter of 16 μm or more is 2% by volume or less. Beyond this, the resolution is reduced and the roughness of the image becomes noticeable. Further, the developed toner is difficult to be transferred onto the transfer paper, and voids are likely to occur in the character portion. Further, at the time of kneading, a colorant or a dispersant for controlling the dispersion state of the magnetic material may be used in combination. Further, the toner base particles may be mixed and surface-modified with a mixer or the like by adding the aforementioned additives.
[0025]
(Career)
As the carrier particles, inorganic / metal particles having appropriate resistance, resin particles in which particles having relatively low resistance are dispersed, particles having a coating layer on a core material using these as cores, etc. may be used. it can.
Examples of materials used for these include the following.
First, examples of inorganic / metal particles that can be used for carrier particles include conventionally known particles such as metals such as iron, cobalt, and nickel; alloys and compounds such as magnetite, hematite, and ferrite. Such carrier particles are generally produced by powder metallurgy. That is, a raw material having a fine primary particle size of 0.3 to 9 microns is weighed, mixed, pre-sintered and then pulverized. Next, this is granulated into spherical particles of approximately 20 to 75 μm in the spray granulation step. Next, it sinters with a baking machine. At the time of sintering, it is preferable to regulate the temperature so that the primary particles on the carrier surface maintain the same shape (so that the primary particles do not become a continuous molten phase). Thereafter, it is classified into arbitrary particles to obtain a carrier core material.
[0026]
Next, as resin for forming the resin particles and / or the coating layer of the carrier particles, for example, polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene; polystyrene, acrylic (for example, polymethyl methacrylate), poly Polyvinyl resins such as acrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, and polyvinylidene resins; vinyl chloride-vinyl acetate copolymers; silicone resins composed of organosiloxane bonds Or modified products thereof (for example, modified products made of alkyd resin, polyester resin, epoxy resin, polyurethane, etc.); polytetrafluoroethylene, polyvinyl fluoride Fluorine resins such as polyvinylidene fluoride and polychlorotrifluoroethylene; polyamides; polyesters; polyurethanes; polycarbonates; amino resins such as urea-formaldehyde resins, melamine-formaldehyde, melamine-formaldehyde-alcohol condensates; and epoxy resins It is done. Among these, silicone resins or modified products thereof, fluorine resins, amino resins, particularly silicone resins or modified products thereof are preferable as the material for the coating layer in terms of preventing toner spent.
[0027]
The silicone resin may be any conventionally known silicone resin, and includes straight silicone consisting only of an organosiloxane bond represented by the following formula and silicone resin modified with alkyd, polyester, epoxy, urethane, etc. It is done.
[Chemical 1]

(In the above formula, R1 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, R2 and R3 are hydrogen groups, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a phenoxy group, and 2 carbon atoms. Or an alkenyl group having 4 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, a hydroxy group, a carboxyl group, an ethylene oxide group, a glycidyl group, or a group represented by the following formula.
[Chemical formula 2]

In the above formula, R4 and R5 are a hydroxy group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, and 2 to 4 carbon atoms. Alkenyloxy group, phenyl group, phenoxy group, k, l, m, n, o, and p represent an integer of 1 or more. )
Each of the above substituents may have a substituent such as an amino group, a hydroxy group, a carboxyl group, a mercapto group, an alkyl group, a phenyl group, an ethylene oxide group, a glycidyl group, or a halogen atom in addition to an unsubstituted one. .
[0028]
In addition, as described above, the low resistance material (conductive material) used for controlling the volume resistivity of the carrier particles dispersed in the resin particles and / or the coating layer may be a conventionally known material. Examples thereof include metals such as iron, gold, and copper; iron oxides such as ferrite and magnetite; white conductive agents (titanium oxide, tin oxide, and zinc oxide); and pigments such as carbon black. Among these, in particular, by using a mixture of furnace black and acetylene black, which is one of carbon blacks, it is possible to effectively adjust the conductivity by adding a small amount of low-resistance fine powder, and furthermore, the resistance of the resin particles / coating layer can be adjusted. Carrier particles excellent in abrasion can be obtained. These low-resistance fine powders preferably have a particle size of about 0.01 to 10 μm, preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, based on 100 parts by weight of resin particles or coating resin. Part is preferred. In addition, a silane coupling agent, a titanium coupling agent, or the like is added to the charge imparting member resin particles and / or the coating layer for the purpose of improving the adhesion with the core particles or improving the dispersibility of the conductivity imparting agent. You may do it.
[0029]
Examples of the silane coupling agent used in the present invention include compounds represented by the following general formula.
YRSiX₃
(In the formula, X is a hydrolyzable group bonded to a silicon atom, such as a chloro group, an alkoxy group, an acetoxy group, an alkylamino group, or a propenoxy group.
Y is an organic functional group that reacts with the organic matrix, such as vinyl group, methacryl group, epoxy group, glycidoxy group, amino group, mercapto group and the like.
R is an alkyl group or alkylene group having 1 to 20 carbon atoms. )
Among these silane coupling agents, an aminosilane coupling agent having an amino group in Y is preferable for obtaining a negatively charged developer, and Y has an epoxy group in order to obtain a positively charged developer. Epoxy silane coupling agents are preferred.
[0030]
As a method for forming the carrier particle coating layer, the coating layer forming liquid may be applied to the surface of the carrier core particles by means of a spraying method, a dipping method, a heating kneader, a heating Henschel mixer, or the like. The thickness of the coating layer is preferably 0.1 to 20 μm.
[0031]
The carrier particles of the present invention consist of spherical particles in which irregularities are formed by a discontinuous phase whose surface state is melted, and a resin coating layer is provided on the surface, so that irregularities on the surface of the spherical particles after coating are discriminated. It is preferable to use a material having such a coating layer that can be used.
Therefore, even if the surface of the core material is a convex part, a coating layer is present, carrier resistance is maintained moderately, and the carrier is long-lived (high durability) with suppressed spending. That is, a uniform coating layer is provided along the circumferential shape of the core material, and the coating layer of the convex portion is thinner than the concave portion, whereas the coating layer of the concave portion is thick. With such a configuration, the presence of the convex portion moderately suppresses an increase in carrier resistance, and the balance between the presence of the concave portion and the convex portion keeps the rising property of charging with the toner good. Does not cause toner adhesion. If there is even a part of the convex portion exposed, toner adheres to the carrier in that portion, leading to a decrease in charge amount and toner scattering.
[0032]
On the other hand, if a coating layer is provided like a shell without matching the circumferential shape of the surface of the core material (the yolk is the core material in the image of an egg), there is no adhesion of spent toner and the coating layer becomes thick, so There is no problem at all even if the coating layer is somewhat scraped with stirring. However, there is no problem with line copy due to edge effects, such as an increase in carrier resistance, an increase in charge amount, a decrease in image density, or an edge effect. It occurs prominently.
The carrier of the present invention is a long-life (high durability) carrier that suppresses an appropriate increase in carrier resistance due to the presence of convex portions and maintains good chargeability with the toner due to the balance of the concave portions. .
[0033]
Carrier particle resistance is 1 × 10⁸~ 1x10¹⁵Ωcm is good. 1 × 10¹⁵If it exceeds Ωcm, the edge effect is large and the roughness of the image is large. Further, although there is no particular problem with character copy, the above-mentioned problems are greatly highlighted when a picture is copied with color copy. Furthermore, the carrier ears become stiff during development, and stripes and unevenness are likely to occur. 1 × 10⁸If it is less than Ωcm, carrier adhesion is likely to occur, and the latent image carrier is damaged by the object, so that the latent image is easily disturbed and the image quality is remarkably lowered.
This resistance is measured as follows. In other words, in an environment of 20 ° C./60% RH, a sample overflows into a cell formed by facing two electrode plates having an area of 10 (length: 4 cm, width: 2.5 cm) at intervals of 2 mm. After that, in this state, the tapping operation for dropping the cell on the flat plate from the position having a height of 15 mm is repeated 30 times to fill the cell with the carrier sample. Next, after removing excess carriers on the cell, a DC electric field of 500 V / cm is applied to the electrode plate to determine the resistance.
[0034]
【Example】
Hereinafter, the present invention will be specifically described based on examples. In addition, a part shows a weight part.
[0035]
Example 1 A toner is prepared by kneading a mixture of the following formulation under the heating of two rolls, then cooled, coarsely pulverized, and classified by pulverization to obtain an average particle size of 7.75 μm and a number percentage of 5 μm or less of 12.85, Toner base particles having a volume% of 16 μm or more and 0.07 were obtained.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: chromium-containing metal complex 1.5 parts
To 100 parts of the toner base particles, silica having an average particle diameter of 0.015 μm was mixed at a ratio of 0.3 part to prepare a negatively chargeable developing toner.
On the other hand, the carrier was a resin mixture having a weight ratio of 75/25 of 2-hydroxyethyl metal relate / methyl methacrylate / styrene copolymer and vinylidene fluoride / tetrafluoroethylene copolymer, and a ferrite core material having an average particle diameter of 50 μm. The carrier was coated by coating 0.75 wt% (based on the core material).
[0036]
Next, prepare a pot made of stainless steel (diameter 60 mm, height 60 mm, volume 50 cm³) Weighed the toner and carrier so that the total amount was 50 g. The toner concentration is set to 1.5% by weight (toner = 0.75 g, carrier = 49.25 g is weighed), the toner and the carrier are charged in a pot, and after mixing at 150 rpm for 10 minutes, the developer toner The charge amount (Q / M) was measured. At this time, the toner consists of toner particles after the addition of an external additive to the toner base particles. Similarly, the toner base particles were charged and the charge amount (Q / M) was measured. The result is as follows.
A: Q / M of toner base particles = −17
B: Q / M of toner particles after addition of external additive = -21
C: average particle diameter of silica 0.015 μm
D: Average particle diameter of toner base particles 7.75 μm
X = 0.024
[0037]
In order to set a developer in a copying machine and test, a two-component developer was prepared by mixing 2.5 parts of the toner with a ratio such that the total amount with the carrier was 100 parts. Then, Imagio 420 (Ricoh Copier) was modified so that the recycled toner returned to the toner replenishing section. When the developer was set in this electrophotographic apparatus and an initial image was formed, a good image was obtained. Furthermore, when a continuous sheet passing test of 100,000 sheets was performed, a good image was found and no toner scattering was observed in the copying machine, and the copying process was stopped halfway and the toner image was observed on the latent image carrier. It was confirmed that there was no problem at all, and there was no problem. Thereafter, a test was conducted for continuous 10,000 sheets in each environment of 10 ° C./15% and 30 ° C./90%, but no particular problem occurred.
[0038]
Comparative Example 1
The toner was kneaded with a mixture of the following formulation under the heating of two rolls, then cooled, coarsely pulverized, and pulverized and classified to obtain toner base particles having an average particle size of 3.6 μm.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: 0.2 part of chromium-containing metal complex
To 100 parts of the toner base particles, silica having an average particle diameter of 0.29 μm was mixed at a ratio of 0.7 part to prepare a negatively chargeable developing toner.
On the other hand, as a carrier, a ferrite core material having an average particle diameter of 50 μm is prepared by mixing a resin mixture of 2-hydroxyethyl metal acrylate / methyl methacrylate / styrene copolymer and vinylidene fluoride / tetrafluoroethylene copolymer in an 80/20 weight ratio. The carrier was coated by coating 0.75 wt% (based on the core material).
[0039]
Next, prepare a pot made of stainless steel (diameter 60 mm, height 60 mm, volume 50 cm³) Weighed the toner and carrier so that the total amount was 50 g. The toner concentration is set to 1.5% by weight (toner = 0.75 g, carrier = 49.25 g is weighed), the toner and the carrier are charged in a pot, and after mixing at 150 rpm for 10 minutes, the developer toner is charged. The quantity (Q / M) was measured. At this time, the toner consists of toner particles after the addition of an external additive to the toner base particles. Similarly, the toner base particles were charged and the charge amount (Q / M) was measured. The result is as follows.
A: Q / M of toner base particles = 1
B: Q / M of toner particles after addition of external additive = −35
C: Average particle diameter of silica 0.29 μm
D: Average particle size of toner base particles 3.6 μm
X = −2.8
[0040]
In order to set a developer in a copying machine and test, a two-component developer was prepared by mixing 2.5 parts of the toner with a ratio such that the total amount with the carrier was 100 parts. Then, Imagio 420 (Ricoh Copier) was modified so that the recycled toner returned to the toner replenishing section. When the developer was set in the electrophotographic apparatus and an initial image was formed, the image density was low and the image was extremely uneven.
Furthermore, when a continuous paper test of 1,000 sheets was performed, the image was further soiled, and toner scattering occurred remarkably in the copying machine, and the copying process was stopped halfway to observe the latent image carrier. As a result, it was confirmed that the amount of dirt and additives due to the toner was remarkably large. At this point, the developer was observed with an electron microscope (SEM), and many floating additives were confirmed.
[0041]
Comparative Example 2
The toner was kneaded with a mixture of the following formulation under the heating of two rolls, then cooled, coarsely pulverized, and pulverized and classified to obtain toner base particles having an average particle diameter of 3.7 μm.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: 0.2 part of quaternary ammonium salt
A positively chargeable developing toner was prepared by mixing 100 parts of the toner base particles with 0.7 parts of silica having an average particle diameter of 0.31 μm.
On the other hand, the carrier is a 20/80 weight ratio resin mixture of 2-hydroxyethyl metal relate / methyl methacrylate / styrene copolymer and vinylidene fluoride / tetrafluoroethylene copolymer, and a ferrite core material having an average particle diameter of 50 μm. The carrier was coated by coating 0.75 wt% (based on the core material).
[0042]
Next, prepare a pot made of stainless steel (diameter 60 mm, height 60 mm, volume 50 cm³) Weighed the toner and carrier so that the total amount was 50 g. The toner concentration is set to 1.5% by weight (toner = 0.75 g, carrier = 49.25 g is weighed), the toner and carrier are charged into the pot, and the mixture is mixed at 150 rpm for 10 minutes, and then the developer is charged. The quantity (Q / M) was measured. At this time, the toner is composed of toner particles obtained by adding an external additive to the toner base particles. Similarly, the toner base particles were charged and the charge amount (Q / M) was measured. The result is as follows.
A: Q / M of toner base particles = 1
B: Q / M of toner particles after addition of external additive = 31
C: Average particle diameter of silica 0.31 μm
D: Average particle diameter of toner base particles 3.7 μm
X = 2.6
[0043]
In order to set a developer on a copying machine and test, a two-component developer was prepared by mixing 2.5 parts of the toner with a ratio such that the total amount with the carrier was 100 parts. Then, the spiro 2210 (Ricoh copier) was modified so that the recycled toner returned to the toner replenishing section. When the developer was set in the electrophotographic apparatus and an initial image was formed, the image density was low and the image was extremely uneven. Further, when a continuous sheet passing test of 1000 sheets was performed, the image was further soiled, and toner scattering was remarkably generated in the copying machine, and the copying process was stopped halfway and observed on the latent image carrier. As a result, it was confirmed that the amount of dirt and additives due to the toner was extremely large. At this point, the developer was observed with an electron microscope (SEM), and many floating additives were confirmed.
[0044]
Example 2
The toner was kneaded with a mixture of the following formulation under the heating of two rolls, then cooled, coarsely pulverized, and pulverized and classified to obtain toner base particles having an average particle size of 4.5 μm.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: 0.2 part of chromium-containing metal complex
To 100 parts of the toner base particles, silica having an average particle size of 0.3 μm was mixed at a ratio of 0.7 part to prepare a negatively chargeable developing toner.
On the other hand, the carrier is a ferrite core material having a weight ratio of 75/25 of 2-hydroxyethyl metal relate / methyl methacrylate / styrene copolymer and vinylidene fluoride / tetrafluoroethylene copolymer and having an average particle diameter of 50 μm. The carrier was coated by coating 0.75 wt% (based on the core material).
[0045]
Next, prepare a pot made of stainless steel (diameter 60 mm, height 60 mm, volume 50 cm³) Weighed the toner and carrier so that the total amount was 50 g. The toner concentration is set to 1.5% by weight (toner = 0.75 g, carrier = 49.25 g is weighed), the toner and carrier are charged into the pot, and the mixture is mixed at 150 rpm for 10 minutes, and then the developer is charged. The quantity (Q / M) was measured. At this time, the toner is composed of toner particles obtained by adding an external additive to the toner base particles. Similarly, the toner base particles were charged and the charge amount (Q / M) was measured. The result is as follows.
A: Q / M of toner base particles = 1
B: Q / M of toner particles after addition of external additive = −35
C: Average particle diameter of silica 0.3 μm
D: Average particle diameter of toner base particles 4.5 μm
X = −2.3
[0046]
In order to set a developer in a copying machine and test, a two-component developer was prepared by mixing 2.5 parts of the toner with a ratio such that the total amount with the carrier was 100 parts. Then, Imagio 420 (Ricoh Copier) was modified so that the recycled toner returned to the toner replenishing section. When the developer was set in this electrophotographic apparatus and an initial image was formed, a good image was obtained. Furthermore, when a continuous sheet passing test of 100,000 sheets was performed, a good image was found and no toner scattering was observed in the copying machine, and the copying process was stopped halfway and the toner image was observed on the latent image carrier. It was confirmed that there was no problem at all, and there was no problem. Thereafter, a test was conducted for continuous 10,000 sheets in each environment of 10 ° C./15% and 30 ° C./90%, but no particular problem occurred.
[0047]
Example 3
The toner was kneaded with a mixture of the following formulation under the heating of two rolls, then cooled, coarsely pulverized, and pulverized and classified to obtain toner base particles having an average particle size of 4.5 μm.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: 0.2 part of quaternary ammonium salt
A positively chargeable developing toner was prepared by mixing 100 parts of the toner base particles with 0.7 parts of silica having an average particle size of 0.3 μm.
On the other hand, the carrier is a 20/80 weight ratio resin mixture of 2-hydroxyethyl metal relate / methyl methacrylate / styrene copolymer and vinylidene fluoride / tetrafluoroethylene copolymer, and a ferrite core material having an average particle diameter of 50 μm. The carrier was coated by coating 0.75 wt% (based on the core material).
[0048]
Next, prepare a pot made of stainless steel (diameter 60 mm, height 60 mm, volume 50 cm³) Weighed the toner and carrier so that the total amount was 50 g. The toner concentration is set to 1.5% by weight (toner = 0.75 g, carrier = 49.25 g is weighed), the toner and carrier are charged into the pot, and the mixture is mixed at 150 rpm for 10 minutes, and then the developer is charged. The quantity (Q / M) was measured. The toner at this time was composed of toner particles obtained by adding external additives to the toner base particles, and the toner base particles were charged in the same manner and the charge amount (Q / M) was measured. The result is as follows.
A: Q / M of toner base particles = 1
B: Q / M of toner particles after addition of external additive = 35
C: Average particle diameter of silica 0.3 μm
D: Average particle diameter of toner base particles 4.5 μm
X = 2.3
[0049]
In order to set a developer in a copying machine and test, a two-component developer was prepared by mixing 2.5 parts of the toner with a ratio such that the total amount with the carrier was 100 parts. Then, the Spirio 2210 Ricoh Copier) was modified so that the recycled toner returned to the toner replenishing section. When the developer was set in this electrophotographic apparatus and an initial image was formed, a good image was obtained. Furthermore, when a continuous sheet passing test of 100,000 sheets was performed, a good image was found and no toner scattering was observed in the copying machine, and the copying process was stopped halfway and the toner image was observed on the latent image carrier. It was confirmed that there was no problem at all, and there was no problem. Thereafter, a test was conducted for continuous 10,000 sheets in each environment of 10 ° C./15% and 30 ° C./90%, but no particular problem occurred.
[0050]
Example 4
In Example 1, a toner was prepared in the same manner as in Example 1 except that the charge control agent was changed from a chromium-containing metal complex to a zinc salicylate derivative (Bontron E84, manufactured by Orient Chemical Co., Ltd.). When tested, the same results as in Example 1 were obtained.
[0051]
Example 5
For the toner, a mixture of the following formulation is kneaded under the heating of two rolls, then cooled, coarsely pulverized, and pulverized and classified, and the average particle size is 7.75 μm, the number% of 5 μm or less is 12.85, 16 μm or more. Toner base particles having a volume% of 0.07 were obtained.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: chromium-containing metal complex 1.5 parts
To 100 parts of the toner base particles, 0.6 parts of silica having an average particle diameter of 0.018 μm and 0.2 parts of titanium having an average particle diameter of 0.023 μm are mixed to prepare a negatively chargeable developing toner. did. The same carrier as in Example 1 was used, a developer was prepared in the same manner as in Example 1, and each charge amount (Q / M) was measured. The result is as follows.
A: Q / M of toner base particles = −17
B: Q / M of toner particles after addition of external additive = −19
C: (average particle diameter of silica 0.018 μm) + (average particle diameter of titanium 0.023 μm) = 0.041
D: Average particle diameter of toner base particles 7.75 μm
X = 0.0059
Next, the same test as in Example 1 was performed, and the same result as in Example 1 was obtained.
[0052]
Example 6
In Example 1, when it tested similarly to Example 1 except having replaced with the thing (TS-720, Cabot company make) which processed the silica with the organic silicon compound, the result similar to Example 1 was obtained.
[0053]
Example 7
In Example 1, a toner and a developer were prepared in the same manner as in Example 1 except that the charge control agent was changed from the chromium-containing metal complex to the salicylic acid iron salt in the toner formulation. The same results as in Example 1 were obtained.
[0054]
Example 8
The toner was kneaded with a mixture of the following formulation under heating of two rolls, then cooled, coarsely pulverized, and pulverized and classified to obtain toner base particles having an average particle diameter of 7.75 μm.
Binder resin: 100 parts of styrene / acrylic resin
Colorant: 11 parts of carbon black
Charge control agent: chromium-containing metal complex 1.5 parts
Wax: 5.5 parts paraffin wax
To 100 parts of the toner base particles, silica having an average particle diameter of 0.015 μm was mixed at a ratio of 0.3 part to prepare a negatively chargeable developing toner. On the other hand, when the carrier was tested in the same manner as in Example 1 using the carrier of Example 1, the same result as in Example 1 was obtained.
[0055]
Example 9
The toner of Example 1 was used.
On the other hand, a coating solution was prepared according to the following prescription when preparing the carrier.
Silicone resin liquid: SR2411 (Toray Dow Corning) 300 parts
1500 parts of toluene
The above coating solution was coated on ferrite having an average particle diameter of 50 μm consisting of a core material surface having irregularities. After coating, the silicon film was cured by heating at 230 ° C. for 2 hours to obtain carrier particles having a coating layer. When the surface of the coated carrier particles was observed with a scanning electron microscope (SEM) or a scanning tunneling microscope (STM), the surface irregularities could be clearly observed even after coating. Further, it was confirmed by the electron beam microanalyzer that Si element was also present in the convex portion.
When this carrier and toner were used and tested in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0056]
Example 10
The toner of Example 1 was used.
On the other hand, the coating liquid was adjusted according to the following formulation in the preparation of the carrier. The core material was coated in the same manner as in Example 9.
Silicone resin liquid: SR2411 (Toray Dow Corning) 300 parts
Conductive agent: 4 parts of Kechen Black ECDJ600
(Lion Akzo) Toluene 1500 parts
When this carrier and toner were used and tested in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0057]
Example 11
The toner of Example 1 was used.
On the other hand, the coating liquid was adjusted according to the following formulation in the preparation of the carrier. The core material was coated in the same manner as in Example 9.
Silicone resin liquid: SR2411 (Toray Dow Corning) 300 parts
Conductive agent: 4 parts of Kechen Black ECDJ600
(Lion Akzo)
Coupling agent: KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) 8 parts
1500 parts of toluene
When this carrier and toner were used and tested in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0058]
Example 12
<Yellow Toner>
A yellow toner was prepared according to the following toner formulation.
100 parts of polyester resin
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
Charge control agent: Salicylic acid Zn salt (Bontron E84, manufactured by Orient Chemical Co., Ltd.) 2 parts
The mixture of the above formulation was pre-kneaded with a mixer. Then, after melt-kneading with a three-roll mill, after cooling and coarsely pulverizing to 0.5 to 3 mm, further pulverization and classification were performed, and the average particle size was 7.75 μm, the number% of 5 μm or less was 12.85, 16 μm or more. A yellow toner having a volume% of 0.07 was obtained.
[0059]
A negatively charged toner was obtained by mixing 0.5 parts of 0.016 μm silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) with 100 parts of the toner.
On the other hand, the carrier of Example 9 was used, and the charge amount of each of the toner base particles and the toner particles after adding the external additive to the toner base particles was measured in the same manner as in Example 1. The result is as follows.
A: Q / M of toner base particles = −18
B: Q / M of toner particles after addition of external additive = −23
C: average particle diameter of silica 0.016 μm
D: Average particle diameter of toner base particles 7.75 μm
X = 0.026
[0060]
<Magenta Toner>
A magenta toner was prepared according to the following toner formulation.
100 parts of polyester resin
Magenta colorant: C.I. I. Pigment Red 122 4 parts
Charge control agent: Salicylic acid Zn salt (Bontron E84, manufactured by Orient Chemical Co., Ltd.) 2 parts
The mixture of the above formulation was pre-kneaded with a mixer. Then, after melt-kneading with a three-roll mill, after cooling and coarsely pulverizing to 0.5 to 3 mm, further pulverization and classification were performed, and the average particle size was 7.75 μm, the number% of 5 μm or less was 12.85, 16 μm or more. A magenta toner having a volume% of 0.07 was obtained.
[0061]
A negatively charged toner was obtained by mixing 0.5 parts of 0.016 μm silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) with 100 parts of the toner.
On the other hand, the carrier of Example 9 was used, and the charge amount of each of the toner base particles and the toner particles after adding the external additive to the toner base particles was measured in the same manner as in Example 1. The result is as follows.
A: Q / M of toner base particles = −14
B: Q / M of toner particles after addition of external additive = −19
C: average particle diameter of silica 0.016 μm
D: Average particle diameter of toner base particles 7.75 μm
X = 0.0028
[0062]
<Cyan Toner>
A cyan toner was prepared according to the following toner formulation.
100 parts of polyester resin
Cyan colorant: C.I. I. Pigment Bull-15: 3 3 parts
Charge control agent: Salicylic acid Zn salt (Bontron E84, manufactured by Orient Chemical Co., Ltd.) 2 parts
The mixture of the above formulation was pre-kneaded with a mixer. Then, after melt-kneading with a three-roll mill, after cooling and coarsely pulverizing to 0.5 to 3 mm, further pulverization and classification were performed, and the average particle size was 7.75 μm, the number% of 5 μm or less was 12.85, 16 μm or more. A cyan toner having a volume% of 0.07 was obtained.
[0063]
A negatively chargeable toner was obtained by mixing 0.5 parts of 0.016 μm silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) with 100 parts of the toner.
On the other hand, the carrier of Example 9 was used, and the charge amount of each of the toner base particles and the toner particles after adding the external additive to the toner base particles was measured in the same manner as in Example 1. The result is as follows.
A: Q / M of toner base particles = −18
B: Q / M of toner particles after addition of external additive = −22
C: average particle diameter of silica 0.016 μm
D: Average particle diameter of toner base particles 7.75 μm
X = 0.0025
[0064]
<Black Toner>
A black toner was prepared according to the following toner formulation.
100 parts of polyester resin
Black colorant: 8 parts of carbon black
Charge control agent: Salicylic acid Zn salt (Bontron E84, manufactured by Orient Chemical Co., Ltd.) 2 parts
The mixture of the above formulation was pre-kneaded with a mixer. Then, after melt-kneading with a three-roll mill, after cooling and coarsely pulverizing to 0.5 to 3 mm, further pulverization and classification were performed, and the average particle size was 7.75 μm, the number% of 5 μm or less was 12.85, 16 μm or more. A black toner having a volume% of 0.07 was obtained.
[0065]
A negatively chargeable toner was obtained by mixing 0.5 parts of 0.016 μm silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) with 100 parts of the toner.
On the other hand, the carrier of Example 9 was used, and the charge amount of each of the toner base particles and the toner particles after adding the external additive to the toner base particles was measured in the same manner as in Example 1. The result is as follows.
A: Q / M of toner base particles = −13
B: Q / M of toner particles after addition of external additive = −18
C: average particle diameter of silica 0.016 μm
D: Average particle diameter of toner base particles 7.75 μm
X = 0.0029
[0066]
Next, the carrier of Example 9 was used, and the yellow, magenta, cyan, and black developers were prepared by mixing 5 parts of each color toner and the carrier in a ratio of 100 parts. . The developer for each color is modified in the tail 750 (Ricoh color copier) and set in a copier in which recycled toner returns to the toner replenishing section. No toner dust was observed, no toner was lost in the character area, moderate image gloss was maintained, and there was no background smearing, resulting in a good image. Further, after images were taken out in respective environments of 10 ° C./30% and 30 ° C./90%, good images were obtained in any of the images after 10,000 copies were made in each environment.
[0067]
Example 13
The toner of Example 1 was used.
On the other hand, the carrier was prepared by adjusting the coating liquid according to the following formulation and covering the core material.
Example of synthesis of acrylic resin having hydroxyl group: 700 g of xylene and 300 g of butanol were charged in a nitrogen stream while stirring with a stirrer, heated to 100 ° C., 400 g of styrene, 160 g of methyl methacrylate, 200 g of n-butyl acrylate, methacryl A mixture of 30 g of acid, 100 g of 2-hydroxyethyl acrylate, and 10 g of azobisisobutyronitrile as a polymerization initiator was added dropwise over 5 hours. Thereafter, the contents were further reacted for 6 hours to obtain a resin having a solid content of 50% by weight. (Hydroxyl value: 41 KOH mg / g, number average molecular weight 1400)
1000 parts of Cu-Zn ferrite (manufactured by Powder Tech Co., Ltd., average particle size 50 μm, F-300)
Fully substituted methylated benzoguanamine (degree of polymerization 1.65, solid content 77% by weight) 2.6 parts
Acrylic resin (the above synthetic product: solid content 50% by weight) 10 parts
300 parts of toluene
The methylated guanamine, acrylic resin and toluene were mixed to prepare a coating solution. The temperature of the fluidized bed type coating apparatus charged with the ferrite was kept at about 60 ° C., and the coating liquid was sprayed. After spraying, it was dried for about 10 minutes and taken out. Next, the carrier was treated in an electric furnace at 150 ° C. for 1 hour, cooled and crushed to obtain a resin-coated carrier having a thickness of 0.2 μm.
When this carrier and toner were used and tested in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0068]
Example 14
The toner of Example 1 was used.
On the other hand, the carrier was prepared by adjusting the coating liquid according to the following formulation and covering the core material.
Example of synthesis of acrylic resin having hydroxyl group: 700 g of xylene and 300 g of butanol were charged in a nitrogen stream while stirring with a stirrer, heated to 100 ° C., 400 g of styrene, 160 g of methyl methacrylate, 200 g of n-butyl acrylate, methacryl A mixture of 30 g of acid, 100 g of 2-hydroxyethyl acrylate, and 10 g of azobisisobutyronitrile as a polymerization initiator was added dropwise over 5 hours. Thereafter, the contents were further reacted for 6 hours to obtain a resin having a solid content of 50% by weight. (Hydroxyl value: 41 KOH mg / g, number average molecular weight 1400) Cu—Zn ferrite (manufactured by Powdertech, average particle size 50 μm, F-300) 1000 parts
Fully substituted methylated benzoguanamine (degree of polymerization 1.65, solid content 77% by weight) 2.6 parts
Acrylic resin (the above synthetic product: solid content 50% by weight) 10 parts
Conductive material: 2.5 parts of Kechen Black ECDJ600
(Lion Akzo)
300 parts of toluene
The methylated guanamine, acrylic resin and toluene were mixed to prepare a coating solution. The temperature of the fluidized bed type coating apparatus charged with the ferrite was kept at about 60 ° C., and the coating liquid was sprayed. After spraying, it was dried for about 10 minutes and taken out. Next, the carrier was treated in an electric furnace at 150 ° C. for 1 hour, cooled and crushed to obtain a resin-coated carrier having a thickness of 0.2 μm.
When this carrier and toner were used and tested in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0069]
Example 15
A polymerized toner was prepared as follows.
90 parts of styrene monomer
55 parts of n-butyl methacrylate
Charge control agent (Spiron Black TRH, Hodogaya Chemical Co., Ltd.) 35 parts
Coloring agent (Raven 410 manufactured by Columbia Chemical Co.) 13 parts
The above ingredients were blended, and polymerization was carried out in a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), and the polymerization was stopped at a particle size of 6.8 μm. After washing with water and drying, polymerized toner particles were obtained. The same additive as in Example 1 was added to this toner to prepare a negatively chargeable developing toner.
Moreover, when the carrier was tested in the same manner as in Example 1 using the carrier of Example 1, the same result as in Example 1 was obtained.
[0070]
【The invention's effect】
In the present invention, the charge amount of the toner base particles is A, the toner charge amount B after the external additive is added to the toner base particles, the sum of the average particle diameters of the external additives is ΣC, and the toner base particle size is D. When the toner satisfying the following relational expression is used, even if the cleaned toner is recycled, the toner is not scattered in the machine, and the electrostatic latent image carrier is not contaminated. Thus, it is possible to provide a two-component developer capable of forming an excellent image with no deterioration in image quality even when the paper is continuously passed in the above environment.
X = (B / A) × (ΣC / D)
-2.3 ≦ X ≦ 2.3 (where X ≠ 0)

Claims (5)

A method of developing an electrostatic latent image on an electrostatic latent image carrier by a developing unit in which a toner layer is formed on a developer carrier, wherein the developing unit includes a carrier and a toner. Component-based developer is stored, and the developer is circulated and conveyed on the developer carrier, and the electrostatic latent image is developed in the development area in the gap between the developer and the electrostatic latent image carrier facing thereto. The toner image formed on the latent image carrier is transferred onto the transfer member one or more times, the electrostatic latent image carrier is cleaned by a cleaning unit, and the toner cleaned by the cleaning unit is toner The toner is returned to the developing unit or the replenishing toner unit via the collection device and reused as recycled toner. The electrostatic latent image carrier is then prepared for the formation of the next electrostatic latent image. After being transferred to the final transfer member, the fixing section A two-component developer used in a more fixed image forming method, wherein the toner particles constituting the developer are at least one or more external additives added to base particles comprising at least a colorant, a binder resin, and a charge control agent. made from those agents which have been added, when the charge amount of the toner base particles a, and the toner charge amount after adding the external additive and B on the toner base particles, a and B are both negatively charged amount, and A two-component developer satisfying the following relational expression, where ΣC is the sum of the average particle diameters of the external additives and D is the average particle diameter of the toner base particles.
1 ≦ (B / A) ≦ (−21) / (− 17)
X = (B / A) × (ΣC / D)
0.0024 ≦ X ≦ 0.0059   The two-component developer according to claim 1, wherein the charge control agent is a salicylic acid metal salt and / or a metal salt of a salicylic acid derivative.   A coating layer in which the carrier particles are made of a resin selected from a silicone resin, a fluorine resin, a mixture of a fluorine resin and a styrene / acrylic copolymer, an amino resin, and a mixture of an amino resin and a styrene / acrylic copolymer; The two-component developer according to claim 1, wherein the two-component developer is contained.   The two-component developer according to claim 1, wherein the carrier particles have a coating layer containing a conductive material.   The carrier particles are spherical particles, and the surface crystal state is made of a discontinuous phase in which a melted phase is formed, and a resin coating layer is provided on the surface, and the coated spherical particle surface has uneven portions. The two-component developer according to claim 1, wherein the two-component developer has a distinguishable coating layer.